1. Field of the Invention
The invention relates to the field of computer system maintenance and management, and in particular, to a way of providing enclosure services over a high-speed, point-to-point serial bus.
2. Background Information
The computer industry is presently expanding on approaches for providing system enclosure services in computer systems. As is generally understood in the art, system enclosure services, or simply enclosure services, refers to a number of computer system enclosure maintenance and management/control functions. Enclosure services includes a group of related functions aimed at managing the enclosure environment. These functions include, for example, sensing and controlling power and cooling apparatus, but may also include such functions as managing vital product data (VPD) information, that is, information about what devices are installed and where, within the computer system.
Enclosure services are generally provided by enabling low-level communication paths inside a computer enclosure and between computer enclosures, in the case of a computer system with multiple enclosures.
In the industry today, for simple system enclosure services, there are primarily two architectures done over functional I/O (input/output) bus paths. One is the American National Standard for Information Systems-System Enclosure Services (ANSI-SES). ANSI-SES provides for Small Computer System Interconnect (SCSI) access to system services, i.e., power, cooling, indicators, etc., within an enclosure containing one or more SCSI devices, e.g., direct access storage devices (DASD""s-disk drives). This standard is described in the working draft entitled xe2x80x9cSES SCSI Enclosure Services,xe2x80x9d X3T10/Project 1212-d/Rev 8a, Jan. 18, 1997. SCSI is a well known bus standard. In this disclosure, ANSI-SES may be referred to hereafter as simply xe2x80x98SESxe2x80x99.
The other primary architecture is called SFF 8067 (Small Form Factor) which runs across the standard FC-AL (Fiber Channel-Arbitrated Loop) bus.
Also, formerly under development was a serial I/O bus and protocol called xe2x80x98FutureIOxe2x80x99 (FIO). The FIO bus was a proposed industry standard I/O bus being developed by IBM (IBM is a trademark of International Business Machines Corporation), HP, Compaq, 3COM, Adaptec and CISCO, that would operate at the relatively high speed of 1.25 GHz.
One proposed use of FIO was as a competitive alternative bus attachment for Server I/O expansion boxes, such as SCSI JBOD (Just-a-Bunch-Of-DASD) boxes; FC-AL (Fibre Channel Arbitrated Loop) JBOD boxes; and BOS (Box-Of-Slots) I/O Adapter boxes.
Also formerly under development was an I/O bus promoted by INTEL and others (Dell, Hitachi, NEC, Siemens and Sun Microsystems, etc.) called NGIO (Next Generation I/O). Next Generation I/O architecture was a channel-oriented, switched fabric, serial point-to-point link architecture aimed at meeting the growing needs of I/O reliability, scalability and performance on servers (see, for example, xe2x80x9cNext Generation I/O: A New Approach to Server I/O Architecturesxe2x80x9d a technical white paper, February 1999 available from the NGIO Forum at http://www.ngioforum.org/events/02991357.html).
Recently the best ideas in the FIO and NGIO bus architectures were merged into one specification by server and peripheral vendors. The new system I/O fabric is called InfinBandSM and features a channel-based, switch fabric design that delivers a unified architecture and protocol. This new system I/O will provide an unprecedented range of performance for entry-level servers through high-end data-center class solutions using interoperable links with a choice of bandwidths (0.5 to 6 Giga-Bytes per second) and bus widths (1xc3x97=4 wire xe2x80x9cwidthxe2x80x9d, 4xc3x97=16 wire xe2x80x9cwidthxe2x80x9d and 12xc3x97=48 wire xe2x80x9cwidthxe2x80x9d). Additional information may be found at the web sites of the InfinBandSM Trade Association (www.infinibandta.org) and the system I/O group (www.sysio.org).
However, the above-mentioned system bus advances do not address the continued need for simple enhanced enclosure services methods.
Presently, more sophisticated forms of box-to-box enclosure services are normally achieved using a separate cable and bus (like RS485). The IBM AS/400 SPCN (System Power Control Network) and Intel""s IPMI (Intelligent Platform Management Interface) are examples of this (AS/400 is a trademark of International Business Machines Corporation). A system power control network (SPCN) is disclosed in U.S. Pat. No. 5,117,430, and in copending application Ser. No. 08/912,561, filed Aug. 18, 1997, entitled xe2x80x9cFAIL-SAFE COMMUNICATI/ONS NETWORK FOR USE IN SYSTEM POWER CONTROLxe2x80x9d, which are assigned to the same assignee as the present application. The SPCN communications network is a low volume serial network used to monitor and control power conditions at a plurality of nodes in a computer system, for example, the IBM AS/400. The nodes typically include microprocessors which monitor the status of, and make occasional adjustments to, the power conditions at the respective nodes. A heterogeneous system enclosure services implementation is disclosed in commonly assigned copending application Ser. No. 09/267,778, filed Mar. 15, 1999, entitled xe2x80x9cHETEROGENEOUS SYSTEM ENCLOSURE SERVICES CONNECTION.xe2x80x9d
In addition to their rich function, a primary consideration and justification for basing more elaborate enclosure services on a separate bus and interface, such as the SPCN, is that the investment for this architecture does not have to be repeated for each type of I/O expansion bus that comes along or is available. On the other hand, the rationale behind simple forms of enclosure services is to decrease base homogeneous system costs, and to allow for standardization to enable a minimal set of heterogeneous enclosure services commands.
Most elaborate enclosure services implementations today are proprietary, so heterogeneous communication protocols are not available. Although the above-mentioned copending application Ser. No. 09/267,778, discloses a method and apparatus for a heterogeneous system enclosure services connection solution, other solutions are also needed.
One significant drawback of simple methods-such as ANSI-SES is that it cannot do Server I/O box power control; that is, the powering on and off of Server I/O boxes. The SCSI bus chip-set is designed to run using full power. Therefore, a power on command cannot be received and acted on by a powered off Server I/O box.
FC-AL 8067 also cannot do box power control because the critical interface link path is through the DASD to the box, and is possible only after the FC-AL DASD has full operational power.
There is also known so-called Wake-On-LAN (WOL) technology. Present WOL design allows remote Server boxes to be powered on (i.e., xe2x80x98Wake-Upxe2x80x99) but cannot be used to power the box off (the box xe2x80x98goes-to-sleepxe2x80x99 automatically after a preset period of inactivity).
Thus, presently there is no high-speed serial bus that enables a node to receive and respond to simple commands or to generate alerts after dropping into a minimal power draw mode (auxiliary power). Such an arrangement is needed to provide the Operating System (OS) with the, capability of confirming, among other things, that a device is physically present on the bus. For instance, a command such as the so-called xe2x80x98Are-You-Therexe2x80x99command, is a necessary prerequisite before determining that a device is in a low-power state, or for general hardware resource management.
Therefore, there is a need for a high-speed serial bus arrangement with the ability to have a node drop into a minimal power draw (auxiliary power only) while still maintaining a physical and logical connection mechanism.
A need exists for a way to provide system enclosure services over the functional path, and at the same time allow some control, response, and alerting mechanisms, when the Target device is only running on auxiliary power.
As discussed above, xe2x80x98over-the-functional-pathxe2x80x99 control can advantageously allow heterogeneous system platforms to perform basic enclosure services, and to enable a very low power management mode, in a specified manner. Out-of-band (using a separate path) hardware and software mechanisms, such as SPCN and IPMI, may not be appropriate for simple heterogeneous JBODs and BOS applications due to extra code overhead, code incompatibilities, and extra cabling costs, for example.
Different system vendors have established necessarily complex and costly home-grown architectures to handle homogeneous enclosure services that are unique to their individual brands. Therefore, there is a need for a simple method to allow simple heterogeneous enclosure services commands between different brands.
As discussed above, at present there are no solutions to these problems in the marketplace. The InfinBandSM Trade Association system I/O group is presently pursuing a path for simple enclosure services that is limited to Power-On/Off, and perhaps a different method for detecting xe2x80x98Are-You-Therexe2x80x99. The design for those methods is not clearly defined, but it is clear that it does not allow for responses from the Target platform to indicate or confirm a un-powered connection, alerts, failure modes, and/or controlling a Target LED when the Target device is connected to auxiliary power (i.e., minimally-powered).
Therefore, a need exists for a way to provide simple enclosure services over a high-speed, point-to-point, serial bus, which overcomes the limitations of conventional and known systems and methods.
It is, therefore, a principle object of this invention to provide enclosure services over a high-speed, point-to-point, serial bus functional path cable.
It is another object of the invention to provide a method and apparatus that solves the above mentioned problems so that simple heterogeneous enclosure services commands can be used between different brands, and so that system enclosure services can be provided over the functional path while at the same time allowing some control, response, and alerts, when the Target device is only running on auxiliary power.
These and other objects of the present invention are accomplished by the method and apparatus disclosed herein.
According to an embodiment of the invention, a method of doing simple and specific enclosure services across a copper high-speed point-to-point serial bus, such as the InfinBandSM (IB) is provided.
According to an embodiment of the invention, a way is provided for maintaining a minimum enclosure services connection at both ends of a high speed point-to-point serial link which also enables very low power consumption at the minimally-powered end.
According to an embodiment of the invention, a future simple enclosure services (sES) improves on the prior forms of enclosure services, such as ANSI-SES and SFF 8067, by enabling a form of simple system power control of IB attached Server I/O expansion boxes.
Advantageously, according to an aspect of the invention, the functional path is used for providing enclosure services requiring no extra wires, and only a small amount of power, called Auxiliary (Aux) power, is required.
According an aspect of the invention, this method provides an enclosure services interconnect method for simple JBOD and BOS attachments for the IB links.
These and other aspects of the invention will become apparent from the detailed description set forth below.